Modern digital microscopy is more and more multi-modal. More frequently there are found multiple imaging devices and specialized illumination devices. For example, it is not uncommon for a light microscope to be capable of wide-field imaging as well as optical sectioning. Lasers, detectors, scanners, and other devices are now added in ever increasing numbers to a single system. The benefit is that a single specimen can be analyzed in many different ways to increase the amount of information collected. Modern motorized microscopes often are equipped with multiple documentation ports to accommodate multiple devices. These documentation ports are automated and can be switched between with the controlling computer. Currently these devices take several seconds to perform a switch. In many cases this is too slow to see transitory signals. Switching times becomes important for multi-modal systems.
Modern microscopy also takes advantage of high NA (Numerical Aperture) objectives and high resolution imaging. Spherical aberration limits the use of such objectives to only ideal imaging situations. A separate patent application, “Spherical Aberration Correction for an Optical Microscope using a Moving Infinity-Conjugate Relay,” U.S. patent application Ser. No. 12/887,869, filed 22 Sep. 2010, which is incorporated herein by reference in its entirety, describes means for correcting spherical aberration.
In fluorescence microscopes, it is also more common to perform multi-channel imaging, meaning that fluorophores of different colors are sequentially imaged. In multi-channel imaging, a common method of separating the colors is to move different color filters into the optical pathway. During rapid acquisition, the time for the filter to change is often the rate limiting step.